With miniaturization mid three-dimensional structuring of a semiconductor pattern, a slight difference in shape affects an operation characteristic of a device, and shape management needs are increasing. For that reason, high sensitivity and high precision are increasingly required in the seaming electron microscope (SEM) used for inspection, and measurement of semiconductors.
In order to accurately ascertain a shape of the pattern, a method of measuring a three-dimensional shape of the pattern is known. In PTL 1, a method of estimating a taper inclination by acquiring a secondary electron image and a backscattered electron image at an observation site, respectively, and per matching with a secondary electron image and a backscattered electron image acquired in a reference pattern is disclosed. In PTL 2, a method of detecting a secondary electron for each emission angle, for each energy, and estimating a structure in a depth direction in order to obtain information in the depth direction is disclosed. In PTL 3, a method of estimating the depth of a pattern from luminance change at the bottom when an acceleration voltage is changed with respect to a deep hole and deep groove material is disclosed. As a method of estimating a cross-sectional shape using the SEM, there is a model-based library (MBL) method. In the MBL method, a cross-sectional shape of a three-dimensional structure is estimated by comparing secondary electron detection signal intensity distribution obtained by scanning a sample with a primary electron beam and secondary electron signal intensity distribution obtained by being calculated in advance for various cross-sectional shapes. Regarding the MBL, description is made in PTL 4, for example.